The present inventin relates a free station surveying method, especially describe a surveying method that a surveying instrument can be set ay any place as a measuring station and different from the conventional surveying, with restriction of measure station the distance and angle of the third point can be measured in use of the principles of the vision logic, elevation and any elevation level can be surveyed easily and the surveying point also can be set, it can overcome the technical difficulties due to some specific topography which the conventinal surveying can not survey.